


The Triangle Inequality Theorem

by GoddessofBirth



Series: Factoring Out Binomials [2]
Category: Teen Wolf (TV)
Genre: Back in the Stilinski House, Boundaries, Frotting, M/M, Marking, Past Abuse, Stilinski Family Feels, cagey scent marking, slowly, unsure boys, use your words boys, working through things
Language: English
Status: Completed
Published: 2012-07-02
Updated: 2012-07-02
Packaged: 2017-11-09 01:45:34
Rating: Mature
Warnings: Underage
Chapters: 1
Words: 3,491
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/449885
Author URL: https://archiveofourown.org/users/GoddessofBirth/pseuds/GoddessofBirth
Summary: <blockquote class="userstuff">
              <p>The only thing either of them is sure of, is that they're going forward with this thing.  Whatever it is.  The one where they're both sixteen year olds, and clueless, and can't decide if they're tearing down walls or rebuilding them as fast as possible.  Follows directly after <i>The Square Root of Imaginary Numbers.</i></p>
            </blockquote>





	The Triangle Inequality Theorem

The lacrosse game comes and goes. The werewolves all play, and manage not to kill anyone, Stiles keeps the bench nice and warm, and Derek sits in the bleachers, smiling his “I look amiable but I'm really thinking of all the inventive ways I can kill you” smile, while a random forty-something cougar presses her hand against his arm and chats him up. The Argents cast a militaristic shadow over them all, from their position at the very top of the stands.

 

All in all, business as usual.

 

Stiles chews the fingers of his glove and tries not to watch Isaac any more than usual. Tries hard not to remember the feel of his hips under his palms or the texture of the inside of his mouth. He succeeds more or less (less), and since he doesn't play, he's able to avoid any potential locker room shower awkwardness, although he knows that will have to be dealt with sooner rather than later.

 

There's no red in his rearview, and his dad is there when he gets home, half asleep on the couch because he insists on waiting up to check in with Stiles. That's his dad, and he loves him just as much as he worries for him. They eat lunch, and talk, and he's glad it's one of the conversations where he doesn't have to come up with any lies.

 

On his way to bed, his dad lays a hand on his shoulder, and says in a voice weary with more than the need for sleep, “I'm proud of you, son.” And it hurts, maybe more than thinking about his mother hurts, because he knows there's very little he's done in the last few months that would make his father proud at all. Then his dad disappears up the stairs and there's the quiet snick of his door closing. The bottle of Jack is missing from the study and if Stiles hears broken sobbing, he ignores it, because his dad would want him to.

 

He whittles the day away on school work and Skyrim and one very epic masturbation session. It turns out actually _knowing_ what it feels like to come with someone adds all sorts of new dimensions to things, and holy hell he can only imagine what it would be like if he actually has sex with Isa – Stiles cums all over himself before he can even complete the thought, which just confirms the entire point.

 

Scott calls at 6:30.

 

“Hey man, wanna go grab pizza and a movie with me and Allison?”

 

Stiles glances at the clock. His dad leaves for the overnight shift at eight.

 

“Nah, you guys go ahead.”

 

“You sure? I'm paying.”

 

He hears the surprise in Scott's voice; knows it's warranted. When _doesn't_ he want to escape from his house and his creepy werewolf stalker? And when doesn't he want to get out of his own head on his mother's birthday? He knows that's the biggest thing behind the invitation, and it warms him that Scott remembered, when he so often forgets. That's Allison's influence, Stiles knows. She makes Scott a better person, a better friend than he ever was before, even if it had been the very opposite in the beginning.

 

“No, it's cool. I'm just gonna hang out here tonight.”

 

Scott hesitates. “Do you...do you want us to come over there instead?”

 

“No...no! I appreciate it man, but I just...I kind of want to be alone? I'll call you in the morning and we can play World of Warcraft, okay?” Wonderful, now he's lying to _Scott_? And he doesn't even know why, not really. Scott, however, is easy going as always, now that he's lodged his obligatory objection.

 

“Alright, cool. But next time, okay? Allison was telling me about some girl she met at work she wants to set you up with.”

 

Stiles makes a noise that must have indicated approval, because Scott laughs and they exchange goodbyes. Stiles throws himself across his bed and entertains the fantasy that he never convinces Scott to take a walk in the woods to try to get a look at the body of a murdered woman.

 

At 7:55 his father knocks on his door to say good-bye. His eyes are red rimmed, but he's pulled together, smiling and sober. The Stilinski men are always pulled together for each other, always strong enough to keep the fort held down.

 

He hears his dad's car pull out from the driveway at 8:00. At 8:05 he sticks his head out the window and finds Isaac standing beneath it, headed tilted up. Stiles jerks his head back toward his room, and because it's apparently against the werewolf bro code to use a door, Isaac scales the side of the house and Stiles steps back to let him climb over the sill. He has a backpack over one shoulder that he drops on the floor.

 

He slips off his jacket, and the  _satisfaction_ Stiles feels, that he's still wearing his clothes, that he hasn't bothered to change out of Stiles' ratty Fruity Oaty Bars t-shirt, is completely unfamiliar, but he likes it enough that he shivers, even though it's not cold.

 

“Do you sleep in my yard?” he asks.

 

Isaac shrugs as he paces restlessly and aimlessly around Stiles' room. “Sometimes. It depends on what Derek wants. If we're training. If we're running.”

 

“Tonight?”

 

Isaac runs his fingers over Stiles' computer keyboard, flicks the monitor switch on and off. “No. I'm just supposed to watch until you're asleep.”

 

“How come you? Why not Erica or Boyd? How'd you get the short straw?” Stiles picks up _Frankenstein_ from the stack, passes it back and forth between his hands for something to do.

 

“Erica and Boyd have parents. They're expected to be places, expected to be tucked in snug in their beds at night. I don't have that complication. I'm more useful to Derek.”

 

Easier for Derek to  _use_ , Stiles thinks, but doesn't say, instead traces his thumb over the title of the book, while Isaac flips through the papers on Stiles' desk – there's nothing there, he's already stowed anything revealing – and asks, “Why  _Frankenstein_ ?”

 

Isaac smirks and tilts his head to the side. “A man dies and is reborn as a monster? Who wouldn't want to read that?”

 

“Yeah, I think you're missing some of the underlying themes of the book.”

 

Isaac gives one barking, high pitched laugh and shakes his head. “No, no I'm really not.”

 

Stiles gives up and waves his hand at the chair by his desk. “Then sit your ass down. I'm tired of screaming out the window.”

 

* * * * * * * 

 

Thirty minutes later and they've migrated to the bed.

 

It's more comfortable.

 

Really.

 

And Stiles' ass is numb from sitting on the floor.

 

They start out sitting cross-legged, facing each other and on top of the comforter, while Stiles reads and Isaac listens, head straight forward and eyes intense. Then Isaac shifts to laying on his stomach, head propped on his arms. Finally he moves again, and now he's on his back, his head resting in Stiles' lap and eyes closed. Stiles holds the book in one hand; the other has somehow drifted to Isaac's hair, and he's combing idly through it, his fingers occasionally catching in loops of curl. In between page 17 and 18, he pauses to breathe, and Isaac takes advantage of the silence.

 

“You said my hair was stupid.”

 

Stiles snorts and tugs on the locks between his fingers, inadvertently making Isaac tip his head back, the lean line of his throat wide exposed. “It is.”

 

“Liar,” Isaac shoots back, not bothering to open his eyes, his Adam's apple bobbing as he swallows.

 

“Yep,” Stiles hums contentedly, setting the book aside. Enough bullshit. He leans down and Isaac meets him halfway, propping up on his elbows. The kiss is different than this morning. Slower, less frantic, a languid lick of tongues across teeth and lips and the insides of cheeks; Stiles' tongue and teeth keep finding their way back to Isaac's lips, over and over again, like he can maybe lick or scrape all of the mystery out of him, taste what makes him tick.

 

They stay there until it becomes too uncomfortable – as awesomely Spiderman-like as the whole upside down thing may be, the position is still awkward – and Isaac pushes up and over to his knees, pulling Stiles with him. He slides his hands underneath Stiles' shirt, pushes is up to Stiles' neck, and darts in, quick and nervous, to press a biting kiss just below his collar bone.

 

And that...that's new. Despite the mutual orgasming that morning –  _excellent_ mutual orgasming, if Stiles does say so himself – hands and mouths had actually stayed in mostly PG rated places, and Stiles stutters out a surprised sound when Isaac's mouth slips down to brush across his nipple. Stiles jerks, accidentally yanking at Isaac's hair.

 

He starts to apologize, between increasingly gasp-y breaths, when Isaac looks up at him, eyes just barely ringed with yellow. “You should do that more.”

 

Isaac runs his tongue over elongated canines, and Stiles waits for them to retract before grinning. “What? This?” He ignores the way his voice cracks on the last word and pulls, just this side of vicious, at the roots of blond curls.

 

And Isaac freaking  _tackles_ him, bowls him over - like he's nothing, like he's air - then straddles his hips and presses him into the mattress. “Yeah, that.” Then he's shoving Stiles shirt up again, spreading wet licks across his chest and collar bone that he follows with small, sharp nips.

 

Stiles is torn between making a dog joke and just letting his mind go to mush, but the decision is taken from him when Isaac nuzzles up under his neck and then bites his earlobe, hard and solid. He arches up, digging his nails into Isaac's scalp and lower back, mouth open and waiting when Isaac returns to it, tonguing in without hesitation. Their hands are everywhere, scavenger hunting for the best places, the best ways to touch. Stiles finally gets Isaac's shirt off, even though his is trapped somewhere under his armpits and twisted in an unsolvable origami knot.

 

Does Isaac even realize the  _sounds_ he makes? Little gasps and whimpers and groans, interspersed with broken breaths and sighs, and this one particular moaning sound when Stiles cups his ass and rocks him down into him. Mother of Christ it's addicting, makes Stiles blood race, makes him want to push and push at Isaac until those noises are the only ones he ever makes again.

 

He sucks a hickey onto Isaac's shoulder, watches it disappear right in front of him, leans in and does it again. Isaac is lapping at his breastbone, broad strokes of the rough of his tongue. He stops, presses his lips to the skin and then stops again.

 

“Can I...here?” He looks up at Stiles, who is now 100% convinced that yes, he has indeed developed a Beta eye kink, or at least an Isaac Beta eye kink., and that could be all sorts of inconvenient in the future. “Just...here? Nobody will see.”

 

Oh. Isaac wants to  _mark_ him, leave some kind of statement he's been here, touching Stiles. And it shouldn't be a turn on, just like Isaac wearing his things shouldn't be a turn on, but it  _is,_ and they  _are_ , and Stiles can barely get his answer out fast enough.

 

“Yeah. Yeah, okay.”

 

Isaac goes to town in a way Stiles knows means he's going to have a hickey the size of Alaska, and he can't even bring himself to care, possibly because most of his energy is going into gulping in air like it's going out of style. He really, really hopes he doesn't look as much like a fish as he feels, and swear to God he doesn't understand how people can get this on a regular basis and continue to perform normal functions. How do Scott and Allison ever leave the bedroom?

 

When Isaac finishes, he pushes up on his arms to survey his handiwork. He smiles, sharp and feral, teeth a white slash between his lips. “Better than a thousand Lydias.”

 

Which is a weird sort of compliment, but Stiles will take what he can get, and really, his dick isn't complaining. “Yeah, I'm awesome. It's true. Get back down here.”

 

Instead of obeying, Isaac watches Stiles carefully, while he slides fingers from his mark on Stiles' chest, down his stomach, and to the snap on his jeans. He runs his thumb nail over it, toys with the metal for a second, before lifting an eyebrow at Stiles.

 

Okay, and yeah, Stiles wants it, he kind of wants it so bad he whimpers, bucks up a little, but this is him, and  _Isaac_ , and if Derek tells him to kill Stiles tomorrow, the bastard would probably still do it with a bounce in his step. And maybe Stiles is a little scared, and maybe he thinks about the fact he's gone from barely having kissed another person to full on frotting and making out and rounding the bases to third in less than twelve hours, and maybe, just maybe that's worth a little freaking out - 

 

He shakes his head. “No. Just – not...not now, okay.”

 

For Isaac to get angry, to lash out, to turn ugly and snide – Stiles is prepared for any of those reactions. That Isaac looks  _relieved_ , that a tightness in his shoulders - something Stiles hadn't even realized was there – relaxes...that's something Stiles hasn't expected at all.

 

“Okay,” he says, then rolls off to lay beside him, his leg and arm still tangled up in Stiles'. They stare at the ceiling, Stiles' fingers idly tapping on Isaac's side.

 

“You guys played a good game today. Nobody killed anybody, so that's pretty much a win, right?”

 

Isaac nods, his hair brushing Stiles' shoulder. “Boyd wanted to, though. Because we lost.”

 

“Hmm...” Stiles fingers have migrated to Isaac's arm, rubbing at the inside crease of his elbow. The skin is soft, and the calluses on his fingertips catch a little on it.

 

Isaac's voice is drowsy and distracted the next time he speaks. “He broke my arm once.” He makes a choking sound and his whole body draws in on itself. Stiles vaults up on one arm to stare at him, and he can see by the panicked look on his face that whatever he had meant to say, it hadn't been  _that_ .

 

“Your dad?” he asks, because it's the logical conclusion, even if the very idea hurts. He can't imagine the life Isaac led before Derek, and has never found it in himself to blame him for accepting the bite, even if he hates what it turned him – turned _all_ of Derek's pack – into.

 

Isaac laughs, bitter and incredulous. “My dad broke my arm more than once.”

 

Although it coils a knot in his stomach, Stiles can't even say he's all that surprised when he works out  _who_ Isaac is referencing. It's funny, because back when they were all scared, all scrabbling and scrambling to figure out the identity of the Alpha, he almost thinks of Derek as a friend. Maybe not in the same way as Scott, but someone he would worry about if he gets hurt, or want to help if he's in trouble. He would even go so far as to say he develops a little bit of a crush on the asshole, despite his constant threats.

 

And then...and then Derek becomes Alpha. And Stiles watches him systemically seduce his classmates with promises of escape and a better life, watches him try to kill his friends, watches the power of the Alpha twist him into something that makes bile rise in Stiles throat. The night of the Battle of Alpha Hill, the night Derek attempts to kill a sixteen year old girl, is willing to mow down anyone standing in his way, on evidence that even he admits is spotty at best...Stiles can easily pinpoint this as the night he loses his last bit of sympathy for Derek, stops seeing him as anything other than an occasional ally by necessity at best, and an outright danger at worst. The various personality changes Derek has gone through since then has done nothing to change the sentiment.

 

Derek tells Scott and Stiles, more than once, that they just don't get it, that one day they'll understand. Stiles sincerely hopes not, hopes he never,  _ever_ gets to a place where he thinks hurting people is justified, where he smirks and enjoys the fear and pain of others. And if he ever comes to the point where he thinks an expedient murder is better than taking the time to ask for help or truly think, he hopes Scott knows to take him out before he can damage the people around him.

 

Still, he tries to give Derek the benefit of the doubt, because isn't pack supposed to be  _family_ ? Didn't he change Isaac to rescue him from a perversion of the word?

 

“Was it...was it while you guys were training? I mean, it was an accident, right?”

 

Isaac has flipped to his side, facing away from Stiles, but Stiles can still hear him just fine. “I was complaining. He didn't like it.”

 

Stiles closes his eyes, gets a hold on the churning in his stomach and takes a deep breath. “What did you do?”

 

Isaac's shoulder rises and falls. “I don't complain anymore. I'm a fast learner.”

 

Although Stiles really, really wants to show Isaac the awesome power of the Stilinski hug, and although he's almost certain the biggest part of Isaac really wants it, he's also dead certain Isaac would never accept it. Instead, he climbs on Isaac and forces him to his back, then proceeds to kiss him senseless.

 

They don't take off anymore clothes, not even to remove the twisted up wreck of Stiles' shirt, but it doesn't really make a difference. They're young, and probably dumb, and coming is always just around the corner. He doesn't move off of Isaac when they're done, but curls around him, smelling cum and sweat and Isaac and Stiles and laundry detergent. He thinks about what Isaac would feel like skin to skin, what all this would be without clothes between them.

 

Isaac's hand is a tentative brush, up and down his spine, thumbing his neck at the top of every upward stroke; Stiles eyes drift shut and he knows if he let himself, he could sleep like this, sprawled on top of the enemy. He's always been a cuddler, as anyone who's ever had the pleasure of taking care of a drunk Stiles can attest.

 

Finally, Isaac's hand stops at the base of Stiles' spine. He sighs out a long breath. “I need to go.”

 

Stiles moves immediately to let him up, and Isaac rolls off the bed and retrieves his backpack, heading toward the bathroom without asking.

 

“Yeah, sure, help yourself!” Stiles calls after him, before stripping and using a towel in his laundry hamper to clean himself up. He's too tired to bother with a shower tonight, so he just pulls on pajama pants and sits at his desk, halfheartedly considering firing his computer up.

 

Isaac takes barely five minutes in the shower, and when he comes back, he's in his own clothes, hair dripping wet. He throws the borrowed jeans into the hamper, but picks the balled up shirt off the ground, keeps it in his hand. He stares at it before folding it into an untidy square, and not even trying to be discreet, walks over to Stiles' bed and shoves it under his pillow.

 

“Are you _serious_?” This seems way too close to some of the weird crap Scott pulls on Allison, which Stiles still doesn't understand, because neither of them have bothered to explain the whys behind it.

 

Isaac just shrugs. “You can move it. Whatever. I don't care.” He crowds into Stiles space but doesn't actually touch him. “Still like those sausage and pancake things from McDonalds?”

 

Stiles rolls his eyes. “They're called McGriddles. Or a tiny piece of paradise, take your pick. And yes.”

 

“I'll bring breakfast.” Isaac snags his jacket and climbs out the window, leaving Stiles blinking stupidly for the second time in one day.

 

Well, not like he's going to turn down free breakfast. He decides against the computer and crawls underneath his covers, letting his sleepiness slowly pull him down. He slides a hand under his pillow and tangles it in the fabric of the t-shirt; it smells so strongly of Isaac that even Stiles can pick it up, and he can imagine what it's doing to the actual scents surrounding his bed. He falls asleep while trying to figure out a cagey way of asking Allison where she gets all those free condoms.

**Works inspired by this one:**

  * [Factoring Out Binomials](https://archiveofourown.org/works/451208) by [GoddessofBirth](https://archiveofourown.org/users/GoddessofBirth/pseuds/GoddessofBirth)




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